JP4958315B2 - Secondary battery charging device and secondary battery charging method - Google Patents

Description

  The present invention relates to a charging device for a so-called secondary battery such as a lead, nickel metal hydride, or lithium ion battery, and a method for charging the secondary battery.

Conventionally, in charging a secondary battery, it is important to know how much the secondary battery is charged with respect to the storage capacity of the secondary battery during the charging process.
Therefore, charging the battery appropriately and rapidly without damaging the internal structure of the secondary battery while periodically checking whether the secondary battery has reached a fully charged state (state where the charging rate is 100%). 2. Description of the Related Art Secondary battery chargers that can be used are known (see, for example, Patent Document 1).
Also, if the secondary battery is charged many times, the storage capacity will decrease compared to the initial stage due to overcharging, deterioration of the electrolyte solution and electrode plate constituting the secondary battery, etc. In reality, this secondary battery could not be used.
Thus, when charging a secondary battery by intermittent charging, a technique for providing a secondary battery deterioration determination method and apparatus capable of determining the deterioration of the secondary battery without disconnecting the secondary battery from the load is known. (For example, refer to Patent Document 2 and Patent Document 3).

Japanese Patent No. 3430439 Japanese Patent No. 3913443 Japanese Patent No. 3539123

  However, due to the deterioration of the secondary battery, the control in the charge / discharge process greatly deviates from the controllable region and may become uncontrollable. In addition, there is an independent detection mechanism such as a temperature sensor, pressure sensor, smoke sensor, etc. as a method to detect abnormal battery conditions, but charging will be terminated if no abnormalities such as temperature rise or smoke generation are confirmed. There was no.

  Therefore, in view of the problem, the present invention provides a charging device and a charging method for a secondary battery that can stably perform charge control even when charging a secondary battery that has been repeatedly charged and discharged over a long period of time. To do.

  The problem to be solved by the present invention is as described above. Next, means for solving the problem will be described.

  That is, in claim 1, a charging voltage supply means for supplying a charging voltage to the secondary battery, a charging current detection means for detecting the charging current of the secondary battery, and a current for detecting an abnormality in the charging current of the secondary battery An abnormality detecting means; and a charging control means for controlling charging of the secondary battery, wherein the charging control means applies or cuts off the supply state of the charging voltage from the charging voltage supply means to the secondary battery. Switching means for switching to a charging voltage supply state from the application state to the cutoff state by the switching means after the initial charging time has elapsed from the start of charging, and charging to the secondary battery by the switching means after the first predetermined time has elapsed. The voltage supply state is switched from the cut-off state to the application state, the charging current is acquired from the current abnormality detection means after the second predetermined time has elapsed from the switching time, and the third predetermined time has elapsed from the switching time Repeatedly to switch the cutoff state the supply state of the electric voltage from the applied state, in which to terminate charging based on the change trend of the acquired charging current.

  In the present invention, the switching means sets the charging voltage supplied from the charging voltage supply means to the secondary battery to a fully charged equilibrium voltage in the shut-off state, and the charging means in the applied state. The charging voltage supplied from the voltage supply means to the secondary battery is set to a predetermined charging application voltage, and the charging control means determines the charging voltage supplied to the secondary battery from the charging application voltage by the charging voltage supply means. Switching to the full charge equilibrium voltage, and the charging is terminated when the charging current detected by the charging current detecting means after the switching is equal to or lower than a predetermined judgment reference current.

  According to a third aspect of the present invention, the charging control means changes the supply state of the charging voltage until the maximum charging current detected by the current abnormality detecting means decreases by a predetermined value after the initial charging time has elapsed since the start of charging. When the number of times of switching from the shut-off state to the application state by the switching means exceeds a predetermined number, charging is terminated.

  According to a fourth aspect of the present invention, the charge control means detects the charge current detected by the current abnormality detection means last time after the initial charging time has elapsed from the start of charging and after the second predetermined time has elapsed since the switching time. Compared with the charged current, the charge is terminated when the charge current exceeds the previously detected charge current.

  In claim 5, the charge voltage supplied to the secondary battery is switched from the charge application voltage to the full charge equilibrium voltage, and the charge is terminated when the charge current after the change is equal to or lower than a predetermined judgment reference current. End control, and the supply state of the charging voltage is switched from the applied state to the cut-off state by the switching means after the initial charging time has elapsed from the start of charging, and the charging voltage is supplied to the secondary battery by the switching means after the first predetermined time has elapsed. Is switched from the cut-off state to the applied state, the charge current is detected by the charge current detecting means after the second predetermined time has elapsed from the switching time, and the charge voltage supply state is switched from the applied state to the cut-off state after the third predetermined time has elapsed from the switching time And the second charging end control for ending charging based on the detected change tendency of the charging current.

  As effects of the present invention, the following effects can be obtained.

  According to the first aspect, it is possible to reliably terminate the charging of the secondary battery before the abnormality occurs. Therefore, even when charging a secondary battery that has been repeatedly charged and discharged over a long period of time to extend the period during which charging control can be normally performed with respect to the progress of deterioration of the secondary battery, charging control Can be performed stably.

  According to the second aspect, it is possible to reliably terminate the charging of the secondary battery before overcharging occurs. Therefore, even when charging a secondary battery that has been repeatedly charged and discharged over a long period of time to extend the period during which charging control can be normally performed with respect to the progress of deterioration of the secondary battery, charging control Can be performed stably.

  According to the third aspect of the present invention, it is possible to easily and accurately grasp the change tendency of the charging current caused by the battery deterioration and perform the charging control. Therefore, charge control can be performed with high accuracy.

  According to the fourth aspect of the present invention, it is possible to easily and accurately grasp the change tendency of the charging current caused by the battery deterioration and perform the charging control. Therefore, charge control can be performed with high accuracy.

  According to the fifth aspect, the charging of the secondary battery can be surely terminated before overcharging occurs. In addition, the charging of the secondary battery can be reliably terminated before an abnormality occurs. Therefore, even when charging a secondary battery that has been repeatedly charged and discharged over a long period of time to extend the period during which charging control can be normally performed with respect to the progress of deterioration of the secondary battery, charging control Can be performed stably.

The circuit diagram of the charging device which concerns on one Embodiment of this invention. The block diagram which shows the control structure of a charge control apparatus. The control flowchart of 1st charge control. The control flowchart of the 2nd charge control concerning 1st embodiment. The graph which shows the relationship between charging voltage and time passage. The control flow figure of the charge end judgment control concerning one embodiment. The graph which shows the relationship between charging current and charging voltage, and time passage. The control flow figure of the charge end judgment control concerning another embodiment. The graph which shows the relationship between charging current and charging voltage, and time passage. The control flowchart of the 2nd charge control concerning 2nd embodiment. The graph which shows the relationship between charging current and charging voltage, and time passage. The graph which shows the relationship between charging current and charging voltage, and time passage.

  First, the charging device of the secondary battery 100 which is one Example of this invention is demonstrated. Here, the secondary battery 100 refers to a battery that can be repeatedly charged and discharged. The electric energy is converted into chemical energy and stored, and conversely, the stored chemical energy is converted into electric energy and used. A battery that can be used. For example, there are a nickel-cadmium battery, a nickel-hydrogen metal battery, a lithium ion battery, and the like.

As shown in FIG. 1, the charging device 1 includes a charging power source 2 as a charging voltage supply unit that supplies a charging voltage E to the secondary battery 100, and a current abnormality that detects an abnormality in the charging current i _charge of the secondary battery 100. A current abnormality detection circuit 3 as detection means and a charging current detection means 5 for detecting the current of the secondary battery 100 are provided.
In addition, as shown in FIG. 2, the charging device 1 includes a charging control device 4 as a charging control unit that controls charging of the secondary battery 100. The charging control device 4 includes a charging power source 2, a current The abnormality detection circuit 3 and the charging current detection means 5 are connected.
In addition, the charging control device 4 includes a switching unit 11 that switches a supply state of the charging voltage E from the charging power source 2 to the secondary battery 100 to an application state or a cutoff state, and a storage unit 12.

Next, the circuit of the charging device 1 will be described with reference to FIG.
The charging power source 2 is composed of a variable power source and can change the charging voltage E applied to the secondary battery 100.
The current abnormality detection circuit 3 includes a first gate 31, a second gate 32, a third gate 33, a fourth gate 34, and an amplifier 41, each of which includes a detection resistor 21 and a switching element such as a transistor. .
The amplifier 41 is an amplifier circuit that amplifies the difference between two input signals by a constant coefficient. The charging current i _charge calculated from the charging voltage E applied to the secondary battery 100 is input to the plus side of the amplifier 41. On the other hand, the negative side of the amplifier 41, the second criterion current J ₂ calculated from the current detection voltage applied from the current detection power source 22 is input. With this configuration, amplifier 41 may compare the second criterion current J ₂ input to the charging current i _charge and the negative input to the positive side.

The first gate 31, the second gate 32, the third gate 33, and the fourth gate 34 are each formed of an NPN type transistor, and the emitter side is grounded. The first gate 31, the second gate 32, the third gate 33, and the fourth gate 34 are used as a switch circuit that can be switched ON / OFF by switching the base potential to a high potential or a low potential. . Here, by switching the base potential of the first gate 31 from the low potential to the high potential, the first gate 31 is switched from OFF to ON, and the second determination reference current J ₂ input to the minus side of the amplifier 41 is changed. Get smaller. Similarly, the second gate 32, by switching from OFF to ON third gate 33, and the fourth gate 34 in turn, the second criterion current J ₂ is input to the negative side of the amplifier 41 is reduced by a fixed amount Become. Thereby, it becomes possible to reduce the second criterion current J ₂ for which to compare the charge current i _charge by a constant amount.
The charging current detection means 5 detects the check current i _check . Here, the check current is a charging current, and indicates a charging current when a fully charged equilibrium potential E _eq is applied to the secondary battery 100 from the charging power source 2.

Next, charge control will be described with reference to the flowcharts of FIGS.
First, conventional first charge control will be described with reference to FIG.
First, before performing the first charge control, the user inputs the type of the secondary battery 100 to be charged into the charge control device 4, thereby corresponding to the type of the secondary battery 100 from the table of the storage unit 12. and a predetermined charging applied voltage E _s, is selected set and full charge equilibrium potential E _eq. Then, the secondary battery 100 is set in the charging device 1 and a manual switch (not shown) is connected to start the first charging control.

In the first charging control first sets the charging voltage E by the switching means 11 is applied to the secondary battery 100 to a predetermined charging voltage applied E _s (step S10). As a result, a relatively large current flows through the secondary battery 100. Next, it is determined whether or not a predetermined time T ₁₁ elapses (step S20), performs the loop processing until the elapsed. This makes it possible to charge a certain time T ₁₁ holds a predetermined charging applied voltage E _s.

Then, from the state the application of the charging voltage E by the switching means 11 is applied to the secondary battery 100 is set to the charging applied voltage E _s, it switched to a short-circuit state to cut off the charging voltage E (Step S30). Thereby, the electric charge of an electrode interface can be removed. Next, it is determined whether the minimum time T ₁₂ elapses (step S40), performs the loop processing until the elapsed. Thus, it is possible to minimum time T ₁₂ holds the short-circuit state.

Thereafter, the charging voltage E is switched to the fully charged equilibrium potential E _eq from the short circuit state where the charging voltage E is cut off by the switching means 11 (step S50). Next, it is determined whether the short time T ₁₃ elapses (step S60), performs the loop processing until the elapsed. Thus, a predetermined fully charged equilibrium potential E _eq can be short time T ₁₃ is applied.

Then, to obtain the information detected check current _{i check} in a fully charged equilibrium potential _{E eq} by the charging current detecting means 5 (step S70). Here, a determination of the check current _{i check} (step S80), checks the current _i If _check is only to be detected with greater value than the first judgment reference current _{J 1,} fully charged equilibrium potential charging voltage E by the switching means 11 switching from E _eq charging applied voltage _{E s} (step S90). And it returns to step S20 and repeats said flow. On the other hand, when the check current i _check became first criterion current J ₁ below, the secondary battery 100 is in a fully charged state, wherein, to stop the charging.

The first determination reference current J ₁ is a constant and is stored in the storage unit 12. In theory, the first criterion current J ₁ in the fully charged state is the may be set to 0 mA, actually, fully charged equilibrium potential E _eq, there are variations slightly electrode by the battery, thus overcharging in order to prevent, slightly larger than the first determination reference current _{J 1} 0 mA, for example, may be set at about 10mA.

FIG. 5 shows the relationship between the charging voltage E and the passage of time when the first charging control is performed. As shown in FIG. 5, after charging at a charging voltage applied E _s during a predetermined time period T _11, is short-circuited by disconnecting the charging voltage E of minimum time T _12, then HazamaMitsuru minute time T ₁₃ A charge equilibrium potential E _eq is applied. Then, in which again charged at the charging voltage applied E _s during a predetermined time period T _11, repeats the series of voltage change below. Incidentally, when the setting of the short time T ₁₃ and more than 1 second, the step S30 and step S40 can be omitted.

Next, the control flow of the second charging control will be described.
[First embodiment]

The case where 1st charge control and 2nd charge control are used together is demonstrated using FIG.
The second charging control is control for charging the secondary battery 100 that has been repeatedly charged and discharged over a long period of time. That is, the secondary battery 100 may deteriorate and the storage capacity may become extremely small. In such a case, it may check current i _check becomes larger than the first determination reference current J ₁ forever in a fully charged equilibrium potential E _eq, was to become overcharged it can not stop charging. Therefore, by performing the second charge control, the secondary battery 100 that has deteriorated as a result of repeated charge and discharge over a long period of time is charged.

First, it is determined whether or not the initial charging period T20 has elapsed since the start of charging (step S105), and loop processing is performed until the initial period has elapsed. Next, the charging voltage E is switched from the application state to the cutoff state by the switching means 11 (step S110). Here, the cut-off state refers to a state in which the fully charged equilibrium potential E _eq is applied to the secondary battery 100 in the first charge control. In the case of using the first charging control and a second charge control in step S30 in the first charging control, setting the charging applied voltage E _s a charging voltage E by the switching means 11 is applied to the secondary battery 100 from a state in which applied to switch to short-circuit state to cut off the charging voltage E, then in step S40, it is determined whether the minimum time T ₁₂ elapses, performs the loop processing until elapsed, then step In S50, step S110 is processed by performing a series of processes for switching the charging voltage E to the fully charged equilibrium potential E _eq from the short-circuit state in which the charging voltage E is interrupted by the switching unit 11.
Next, it is determined whether a first predetermined time T ₂₁ has elapsed (step S120), it performs the loop processing until the elapsed. Here, the first predetermined time _{T 21} is equal to the time a combination of the minimum time _{T 12} and the minute time _{T 13.} Further, since the minimum time _{T 12} is the minimum time, the first predetermined time _{T 21} is equal to approximately a minute time _{T 13.}
Thereafter, the switching unit 11 switches the supply state of the charging voltage E to the secondary battery 100 from the cutoff state to the applied state (step S130). Here, the applied state, in the first charging control means a state in which a predetermined charging voltage applied E _s to the secondary battery 100 is applied. In the case of using the first charging control and the second charging control, the control of switching from the full charge equilibrium potential E _eq at the first charging control to the predetermined charging voltage applied E _s is, step S130 is processed It will be.

Next, it is determined whether the second predetermined time T ₂₂ elapses from the switching point in step S130 (step S140), performs the loop processing until the elapsed. Thereafter, the charging current i _charge is acquired from the current abnormality detection circuit 3 (step S150). Thereafter, charge end determination control is performed to determine whether or not to end the charge based on the change tendency of the _charge current i _charge (step S160). Then, it is determined whether or not charging is terminated in the charging termination determination control (step S170). When it is determined that charging is terminated, charging is terminated.

If the charging end determination control is not determined charge termination determines whether a third predetermined time T ₂₃ from the switching time has elapsed in step S130 (step S180), performs the loop processing until the elapsed. In the case of using the first charging control and the second charging control, the third predetermined time T ₂₃ is equal to the predetermined time T _11.
Thereafter, the supply state of the charging voltage E is switched from the application state to the cutoff state by the switching means 11 (step S190).
In the case of using the first charging control and a second charge control in step S30 in the first charging control, setting the charging applied voltage E _s a charging voltage E by the switching means 11 is applied to the secondary battery 100 from a state in which applied to switch to short-circuit state to cut off the charging voltage E, then in step S40, it is determined whether the minimum time T ₁₂ elapses, performs the loop processing until elapsed, then step In S50, step S190 is processed by performing a series of processes for switching the charging voltage E to the fully charged equilibrium potential E _eq from the short-circuit state in which the charging voltage E is interrupted by the switching unit 11.

Next, a specific determination method of the charging end determination control for ending charging based on the change tendency of the charging current i _charge in the second charging control will be described.

As the charge end determination control based on the change in the charge current i _charge in the second charge control, the maximum charge current i _max detected by the current abnormality detection circuit 3 after the initial charge time T20 has elapsed from the start of charge in step S130 is a predetermined value Δi. There is a control to terminate the charging when the number m of times the supply state of the charging voltage E is switched from the cutoff state to the application state by the switching means 11 exceeds a predetermined number M.

Here, the maximum charging current i _max detected by the current abnormality detection circuit 3 after the initial charging time T20 has elapsed is processed for the first time in the second charging control when the charging current i _charge decreases as charging progresses. In step S130, the charging current i _charge detected by the current abnormality detection circuit 3 is obtained.

Next, the control flow will be described with reference to FIG.
First, only when step S140 in the second charge control is processed for the first time, the coefficient n and the number m are initialized, and the maximum charging current i _max is stored (step S210).
Then, to calculate the second determination reference current _{J 2} (step S220). Second determination reference current J ₂ is calculated by the following equation.
J ₂ = i _max − (n + 1) Δi
Here, Δi is obtained by dividing the maximum charging current i _max by a predetermined constant N.
Next, it is determined whether or not the charging current i _charge is smaller than the second determination reference current J ₂ (step S230). Charge current _{i charge} is when the second criterion current _{J 2} is smaller than the coefficient n is incremented by 1 (step S240), and the number m to 1 (step S250). Then, it is determined that the charging is continued (step S260), and the process returns.
On the other hand, the charging current _{i charge} is when it is a second determined reference current _{J 2} or more, the number m is increased by one (step S270), the number m is determined whether a predetermined number M smaller (step S280 ). If the number m is equal to or greater than the predetermined number M, it is determined that charging has ended (step S290) and the process returns. If the number m is smaller than the predetermined number M, it is determined that charging is continued (step S300), and the process returns.

For example, when the predetermined number of times M is set to 5 times, as shown in FIG. 7, the number of times of switching from the cut-off state to the applied state is 2 in order to decrease Δi from the maximum charging current i _max . Continue charging.
Further, as shown in FIG. 7, the number of times the charge current i _charge is switched from the cut-off state to the applied state while the charge current i _charge is further decreased by Δi from the second determination reference current J ₂ (= i _max −Δi) is four times. So continue charging. Hereinafter, similarly, it is determined whether or not the number of times of switching from the cut-off state to the application state exceeds 5 times while the charging current i _charge is decreased by Δi from the second determination reference current J ₂ (= i _max −nΔi). If it does not exceed 5 times, continue charging.
As shown in FIG. 7, the number of times of switching from the cut-off state to the application state to further decrease Δi from i _max −2Δi is k times (k> 5), and the charge is terminated because it exceeds five times.

In addition, as the charge end determination control based on the change in the charge current i _charge in the second charge control, after the initial charge time T20 has elapsed from the start of charge (step S105), the second predetermined time from the switching time (step S110). elapsed time (step S140) after detected by the current abnormality detecting circuit 3 to the charge current _{i charge (n),} compared with the charging current _{i charge} that is detected in the previous _(n-1), the charging current _{i charge ( When n)} exceeds the previously detected charging current _{icharge (n-1)} , there is a control for terminating the charging.

The control flow will be described with reference to FIG.
First, only when step S140 in the second charge control is processed for the first time, 1 is substituted for n (step S410). Next, in step S130 of the second charging control immediately before the charge current _{i charge} obtained in the n-th _(n), by substituting the charge current _{i charge} detected by the current abnormality detecting circuit 3, in the storage unit 12 (Step S420). Then, it is determined whether or not the charging current acquired at the nth time is larger than the charging current acquired at the previous time (n−1th time) (step S430). Note that the charging current i _{charge (1)} may be larger than the charging current i _{charge (0)} by storing a sufficiently large value for the previous charging current i _{charge (0)} in the case of n = 1. It is configured not to exist.

  When the charging current acquired at the nth time is equal to or less than the charging current acquired at the previous time ((n-1) th time) (step S440), it is determined that the charging is continued (step S450). ), Return. On the other hand, if the charging current acquired at the nth time is larger than the charging current acquired at the previous time (n-1th time), it is determined that the charging is finished (step S460) and the process returns.

For example, as shown in FIG. 9, when the charge current i _{charge (1)} stored for the first time is compared with the charge current i _{charge (2)} stored for the second time, i _{charge (2)} is i _{charge (1).} From the following, it is determined that charging is continued.

Further, as shown in FIG. 9, when the charging current i _{charge (2)} stored for the second time is compared with the charging current i _{charge (3)} stored for the second time, i _{charge (3)} is i _{charge (2).} From the following, it is determined that charging is continued. Thereafter, the charging end determination control is performed in the same manner after the third time.

Then, for example, as shown in FIG. 9, when comparing the charging current _{i charge} stored in the k-th and _(k) and (k-1) th to the charging current _{i charge} stored _{(k-1), i charge ( Since k)} is larger than i _{charge (k−1)} , it is determined that charging is finished.
With this configuration, when an abnormality occurs in which the charging current i _charge starts to increase after decreasing, charging can be quickly terminated.
[Second Embodiment]

Moreover, the case where only 2nd charge control is applied is demonstrated.
The second charging control is control for charging the secondary battery 100 that has been repeatedly charged and discharged over a long period of time. That is, the secondary battery 100 may deteriorate and the storage capacity may become extremely small. In such a case, the charging could not be stopped for a long time, resulting in overcharging. Therefore, by performing the second charge control, the secondary battery 100 that has deteriorated as a result of repeated charge and discharge over a long period of time is charged.

First, as shown in FIG. 10, it is determined whether or not the initial charging period T20 has elapsed since the start of charging (step S505), and loop processing is performed until it has elapsed. Next, the charging voltage E is switched from the application state to the cutoff state by the switching means 11 (step S510). Here, the interruption state refers to a short-circuit state in which the charging voltage E is interrupted.
Next, it is determined whether a first predetermined time T ₂₁ has elapsed (step S520), it performs the loop processing until the elapsed.
Thereafter, the switching unit 11 switches the supply state of the charging voltage E to the secondary battery 100 from the cut-off state to the application state (step S530). Here, the applied state means a state in which a predetermined charging voltage applied E _s to the secondary battery 100 is applied.

Next, it is determined whether the second predetermined time T ₂₂ from the switching time has elapsed in step S530 (step S540), performs the loop processing until the elapsed. Thereafter, the charging current i _charge is acquired from the current detection circuit 3 (step S550). Thereafter, charge end determination control is performed to determine whether or not to end the charge based on the changing tendency of the _charge current i _charge (step S560). Then, it is determined whether or not charging is terminated in the charging termination determination control (step S570). If it is determined that charging is terminated, charging is terminated.

If the is not determined charging end with a charging end determination control determines whether a third predetermined time T ₂₃ from the switching time has elapsed in step S530 (step S580), performs the loop processing until the elapsed .
Thereafter, the switching unit 11 switches the supply state of the charging voltage E from the applied state to the cut-off state (step S590).

Next, a specific determination method of the charging end determination control for ending charging based on the change tendency of the charging current i _charge in the second charging control will be described.

As charge end determination control based on the change in the charge current i _charge in the second charge control, the maximum charge current i _max detected by the current abnormality detection circuit 3 after the initial charge time T20 has elapsed from the start of charge in step S530 is a predetermined value Δi. There is a control to terminate the charging when the number m of times the supply state of the charging voltage E is switched from the cutoff state to the application state by the switching means 11 exceeds a predetermined number M.

Here, the maximum charging current i _max detected by the current abnormality detection circuit 3 after the initial charging time T20 has elapsed is processed for the first time in the second charging control when the charging current i _charge decreases as charging progresses. In step S530, the charging current i _charge detected by the current abnormality detection circuit 3 is obtained.

Next, the control flow will be described with reference to FIG.
First, only when step S540 in the second charge control is processed for the first time, the coefficient n and the number m are initialized and the maximum charging current i _max is stored (step S210).
Then, to calculate the second determination reference current _{J 2} (step S220). Second determination reference current J ₂ is calculated by the following equation.
J ₂ = i _max − (n + 1) Δi
Here, Δi is obtained by dividing i _max by a predetermined constant N.
Next, it is determined whether or not the charging current i _charge is smaller than the second determination reference current J ₂ (step S230). Charge current _{i charge} is when the second criterion current _{J 2} is smaller than the coefficient n is incremented by 1 (step S240), and substitutes 1 to the number of times m (step S250). Then, it is determined that the charging is continued (step S260), and the process returns.
On the other hand, the charging current _{i charge} is when it is a second determined reference current _{J 2} or more, the number m is increased by one (step S270), the number m is determined whether a predetermined number M smaller (step S280 ). If the number m is equal to or greater than the predetermined number M, it is determined that charging has ended (step S290) and the process returns. If the number m is smaller than the predetermined number M, it is determined that charging is continued (step S300), and the process returns.

For example, when the predetermined number of times M is set to 5 times, as shown in FIG. 11, the number of times of switching from the cut-off state to the applied state is 2 in order to decrease Δi from the maximum charging current i _max . Continue charging.
Further, as shown in FIG. 11, the charging current i _charge is further decreased by Δi from the second determination reference current J ₂ (= i _max −Δi). So continue charging. Hereinafter, similarly, it is determined whether or not the number of times of switching from the cut-off state to the application state exceeds 5 times when the charging current decreases by Δi from the second determination reference current J ₂ (i _max −nΔi). Continue charging if not exceeded.
As shown in FIG. 11, the number of times of switching from the cut-off state to the application state to further decrease Δi from the second determination reference current J ₂ (= i _max −2Δi) is k times (k> 5), and 5 Since it exceeds the number of times, charging ends.

Further, as the charge end determination control based on the change in the charge current i _charge in the second charge control, after the initial charge time T20 has elapsed from the start of charge (step S505), the second predetermined time from the switching time (step S510). _{T 22} has elapsed (step S540) after detected by the current abnormality detecting circuit 3 to the charge current _{i charge} a _(n), compared with the charging current _{i charge} that is detected in the previous _(n-1), the charging current There is a control for terminating charging when i _{charge (n)} exceeds the previously detected charging current i _{charge (n-1)} .

The control flow will be described with reference to FIG.
First, only when step S540 in the second charge control is processed for the first time, 1 is substituted for n (step S410). Next, in step S130 of the second charging control immediately before the charge current _{i charge} obtained in the n-th _(n), by substituting the charge current _{i charge} detected by the current abnormality detecting circuit 3, in the storage unit 12 (Step S420). Then, the charging current _{i charge} obtained in the n-th determines whether the charge current _{i charge} greater than or not the previously obtained ((n-1) th) (step S430). Note that the charging current i _{charge (1)} may be larger than the charging current i _{charge (0)} by storing a sufficiently large value for the previous charging current i _{charge (0)} in the case of n = 1. It is configured not to exist.

  When the charging current acquired at the nth time is equal to or less than the charging current acquired at the previous time ((n-1) th time) (step S440), it is determined that the charging is continued (step S450). ), Return. On the other hand, if the charging current acquired at the nth time is larger than the charging current acquired at the previous time (n-1th time), it is determined that the charging is finished (step S460) and the process returns.

For example, as shown in FIG. 12, when the charge current i _{charge (1)} stored for the first time is compared with the charge current i _{charge (2)} stored for the second time, i _{charge (2)} is i _{charge (1).} From the following, it is determined that charging is continued.

In addition, as shown in FIG. 12, when the charge current i _{charge (2)} stored for the second time is compared with the charge current i _{charge (3)} stored for the second time, i _{charge (3)} is i _{charge (2).} From the following, it is determined that charging is continued. Thereafter, the charging end determination control is performed in the same manner after the third time.

Then, for example, as shown in FIG. 12, when comparing the charging current _{i charge} stored in the k-th and _(k) and (k-1) th to the charging current _{i charge} stored _{(k-1), i charge ( Since k)} is larger than i _{charge (k−1)} , it is determined that charging is finished.
With this configuration, when an abnormality occurs in which the charging current i _charge starts to increase after decreasing, charging can be quickly terminated.

As described above, the charging device 1 of the secondary battery 100 includes the charging power source 2 that supplies the charging voltage E to the secondary battery 100, the charging current detection unit 5 that detects the check current i _check of the secondary battery 100, A current abnormality detection circuit 3 for detecting an abnormality in the charging current i _charge of the secondary battery 100 and a charge control device 4 for controlling the charging of the secondary battery 100 are provided. Switching means 11 for switching the supply state of charging voltage E to secondary battery 100 to an applied state or a cut-off state is provided, and the supply state of charge voltage E is cut off from the applied state by switch means 11 after the initial charging time T20 has elapsed from the start of charging. switching state, switching to the application state to the supply state from the cutoff state of the charging voltage E to the switching unit 11 by the secondary battery 100 after a lapse of a first predetermined time T _21, or switching point Gets the charge current i _charge from the current abnormality detecting circuit 3 after the elapse of the second predetermined time T _22, repeatedly to switch the cutoff state the supply state of the charging voltage E from the switching time point after the lapse of the third predetermined time T ₂₃ from the application state The charging is terminated based on the change tendency of the acquired charging current i _charge .
By configuring in this way, charging of the secondary battery 100 can be reliably terminated before an abnormality occurs. Therefore, even when charging the secondary battery 100 that has been repeatedly charged and discharged over a long period of time, the period in which the charge control can be normally performed with respect to the progress of the deterioration of the secondary battery 100 is attempted. Charge control can be performed stably.

Further, the switching means 11 sets the charging voltage E supplied from the charging power source 2 to the secondary battery 100 to the fully charged equilibrium voltage E _eq in the cut-off state, and from the charging power source 2 in the applied state. by setting the charging voltage E that is supplied to the battery 100 to a predetermined charging voltage applied E _s, the charge control device 4, predetermined charging applied voltage E _s for supplying charging voltage E by the charge power source 2 to the secondary battery 100 switch to full charge balanced voltage E _eq from when the charging current i _charge detected by the current abnormality detecting circuit 3 after the switching is the second criterion current J ₂ below, it is also possible to terminate the charging.
By configuring in this way, charging of the secondary battery 100 can be reliably terminated before an abnormality occurs. Therefore, even when charging the secondary battery 100 that has been repeatedly charged and discharged over a long period of time, the period in which the charge control can be normally performed with respect to the progress of the deterioration of the secondary battery 100 is attempted. Charge control can be performed stably.

Further, the charging control device 4 changes the supply state of the charging voltage E until the maximum charging current i _max detected by the current abnormality detection circuit 3 decreases by a predetermined value Δi after the initial charging time T20 has elapsed from the start of charging. When the number m of times the switching unit 11 switches from the cut-off state to the application state exceeds a predetermined number M, the charging can be terminated.
With this configuration, it is possible to easily and accurately grasp the change tendency of the charging current i _charge and perform charging control. Therefore, charge control can be performed with high accuracy.

The charging control unit 4, an after T20 initial charge time from start of charging, the charging current i _charge detected by the current abnormality detecting circuit 3 from the switching time point after the lapse of the second predetermined time T ₂₂ the _(n), compared with the charging current _{i charge} that is detected in the previous _(n-1), when the charge current _{i charge (n)} exceeds the charging current _{i charge} that is detected in the previous _(n-1), and terminates the charging You can also.
With this configuration, it is possible to easily and accurately grasp the change tendency of the charging current i _charge and perform charging control. Therefore, charge control can be performed with high accuracy.

DESCRIPTION OF SYMBOLS 1 Charging apparatus 2 Charging power supply 3 Current abnormality detection circuit 4 Charging control apparatus 5 Charging current detection means 11 Switching means 100 Secondary battery

Claims (5)

Charging voltage supply means for supplying a charging voltage to the secondary battery;
Charging current detecting means for detecting the charging current of the secondary battery;
Current abnormality detection means for detecting abnormality of the charging current of the secondary battery;
Charging control means for controlling charging of the secondary battery;
Comprising
The charge control means includes
Comprising a switching means for switching the supply state of the charge voltage from the charge voltage supply means to the secondary battery to an applied state or a cutoff state;
After the initial charging time has elapsed from the start of charging, the supply state of the charging voltage is switched from the applied state to the cutoff state by the switching means, and the supply state of the charging voltage to the secondary battery is switched from the cutoff state by the switching means after the first predetermined time has elapsed. Switching to the application state, acquiring a charging current from the current abnormality detecting means after a second predetermined time from the switching time, and switching the supply state of the charging voltage from the application state to the cutoff state after the third predetermined time from the switching time. Repeat and terminate charging based on the change tendency of the acquired charging current,
A rechargeable battery charging device. The switching means sets the charging voltage supplied from the charging voltage supply means to the secondary battery to a fully charged equilibrium voltage in the shut-off state, and the secondary voltage from the charging voltage supply means in the applied state. Set the charging voltage supplied to the battery to a predetermined charging application voltage,
The charge control means includes
The charging voltage supplied to the secondary battery is switched from the charging applied voltage to the fully charged equilibrium voltage by the charging voltage supplying means, and the charging current detected by the charging current detecting means after the switching is equal to or less than a predetermined judgment reference current. When charging ends,
The secondary battery charging device according to claim 1. The charge control means includes
The charging voltage supply state is switched from the cut-off state to the application state by the switching unit until the maximum charging current detected by the current abnormality detection unit decreases by a predetermined value after the initial charging time has elapsed since the start of charging. When the number of times exceeds a predetermined number of times, charging is terminated.
The secondary battery charging device according to claim 1. The charge control means includes
The charging current detected by the current abnormality detecting means after the initial charging time has elapsed from the start of charging and after the second predetermined time has elapsed from the switching time is compared with the charging current detected last time, and the charging current is When charging current detected last time is exceeded, charging is terminated.
The secondary battery charging device according to claim 1. A charge voltage to be supplied to the secondary battery is switched from the charge application voltage to the full charge equilibrium voltage, and when the charge current after the change is equal to or lower than a predetermined judgment reference current, a first charge end control for ending the charge;
After the initial charging time has elapsed from the start of charging, the supply state of the charging voltage is switched from the applied state to the cutoff state by the switching means, and the supply state of the charging voltage to the secondary battery is switched from the cutoff state by the switching means after the first predetermined time has elapsed. Switching to the application state, detecting the charging current by the charging current detecting means after a second predetermined time from the switching time, and switching the supply state of the charging voltage from the application state to the cutoff state after the third predetermined time from the switching time. Repeatedly using the second charging end control for terminating charging based on the detected change tendency of the charging current,
Rechargeable battery charging method.

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